Marcian of Tortona was an early Christian bishop who served the community in what is now northwestern Italy. Born into a pagan family in the province of Alessandria, he reportedly converted to Christianity through the influence of Barnabas. He later held the position of the first bishop of Tortona for forty-five years. Historical records from the eighth century support his role as the leader of the local church, and he is traditionally recognized as a martyr who died for his faith during the second century.